EM Waves & Matter (OCR GCSE Combined Science A (Gateway)) : Revision Note

Katie M

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Katie M

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Interaction of Different Substances

Higher Tier Only

  • When EM waves move from one medium to another the waves might be:

    • Transmitted

    • Absorbed

    • Reflected

    • Refracted

transmission-of-wave, IGCSE & GCSE Physics revision notes

When waves move from one medium to another they can be transmitted, reflected, refracted or absorbed

  • The material interacts differently with different parts of EM spectrum because of the difference in wavelength

  • Whilst some wavelengths might be transmitted, others might be reflected, refracted or absorbed

  • Which of the interactions happen depends on:

    • The wavelength of the waves

    • The material the wave is travelling through

  • For example, glass will:

    • Transmit and/or refract visible light

    • Absorb UV radiation

    • Reflect IR radiation

Refraction of EM Waves

Higher Tier Only

  • Some effects, for example, refraction, are due to the difference in velocity of the waves in different substances

  • Although all electromagnetic waves travel at the same speed in a vacuum, when they encounter certain materials (water, glass, oil) they will slow down

    • How much they slow down depends on the material

    • This slowing of electromagnetic waves causes them to refract

  • A simple example of this is the refraction of visible light when it enters (or leaves) a glass block, although other electromagnetic waves can also refract

refraction-through-different-blocks, IGCSE & GCSE Physics revision notes

When electromagnetic waves pass through matter, their interactions slow them down causing them to refract

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Katie M

Author: Katie M

Expertise: Physics Content Creator

Katie has always been passionate about the sciences, and completed a degree in Astrophysics at Sheffield University. She decided that she wanted to inspire other young people, so moved to Bristol to complete a PGCE in Secondary Science. She particularly loves creating fun and absorbing materials to help students achieve their exam potential.

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